#include<stdio.h>
#include<math.h>

int main()
{
 	double a,b,c,s,area;
 	a=3.67;
 	b=5.43;
 	c=6.21;
 	s=(a+b+c)/2;
 	area=sqrt(s*(s-a)*(s-b)*(s-c));
 	printf("a=%f\tb=%f\tc=%f\n",a,b,c);
 	printf("area=%f\n",area);
 	return 0;
}

